Can homeopathy actually work if someone knows it is a placebo? What if, for example, a skeptical Science 2.0 group was told they got a placebo and that nutritionists were getting medicine? Would we feel better anyway?(1)

Of course it's possible, it just wouldn't be due to magic water. It's a mystery of biology why some people just feel better taking something. That is why homeopathy still exists a few hundred years after its invention even though it has never worked.(2)

Does the placebo effect apply to dogs? Do they understand the concept of medicine? If not, they have a placebo effect.

A recent systematic review of randomized controlled trials in Veterinary Record attempted to find out if homeopathy works for animals. They were able to find 18 papers using criteria such as 'not funded by a homeopath' and did their best to account for bias. What did they find? Not much. This is not a serious field, though it is a growing one, so they ended up with studies using 4 species and 11 different medical conditions - not really controllable.


Link: http://dilbert.com/strips/comic/2010-04-16/

They found two that met criteria for reliable evidence: Homeopathic Coli had a prophylactic effect on pig diarrhea, which is caused by a common coronavirus. That is a tricky determination.  It's difficult to know if the pigs did not get a disease because of homeopathy just because they didn't get it. Even the federal government, which had the audacity to claim there were "jobs saved" due to government subsidies, would not, for example, say, 'more Americans don't have Ebola because the NIH gives Johns Hopkins University $600 million a year'. 

The other study that at least looked legitimate was on bovine mastitis - inflammation of the udders - and the results were that homeopathy was no better than a placebo.

The authors are kind, writing "reliable evidence precluded generalisable conclusions about the efficacy of any particular homeopathic medicine or the impact of individualised homeopathic intervention on any given medical condition in animals". That means homeopathy will not work, even for pets who don't know any better.

So if you meet a veterinarian who claims they can help your animal using homeopathy - remind them that we are not in the 18th century any more. Homeopathy used to be compared to witchcraft but we are a more enlightened, tolerant society now and we recognize that such characterizations are unfair...to witches.

Citation: Mathie RT, Clausen J, 'Review: Veterinary homeopathy: systematic review of medical conditions studied by randomised placebo-controlled trials', Veterinary Record 2014;175:15 373-381 doi: 10.1136/vr.101767

NOTES

(1)  Would the nutritionists be horrified that they were being poisoned by science?

(2) No matter how many hundreds of millions of dollars Democrats give to the National Center for Complementary&Alternative Medicine to make their constituents happy.